Macroglobulinemia. II. Antisera specific for pathological macroglobulins.

Rabbits were immunized with three highly purified macroglobulins, from patients with macroglobulinemia. The antisera reacted with two macroglobulins with sedimentation constants of 19S and 26S of homologous antigen, and cross-reacted with the 7S and 19S globulins of normal gamma(1)-globulin and the heterologous pathological 19S macroglobulins. Exhaustive absorption of these antisera with normal gamma-globulins rendered them specific for the homologous macroglobulins. The antigenic properties of the pathological macroglobulins indicate that these proteins are abnormal.